Microcapillary devices using high dielectric constant materials and related methods

Abstract

A microcapillary device includes a microcapillary tube. An anode is positioned at a first end of the microcapillary tube. A cathode is positioned at a second end of said microcapillary tube. A plurality of electric field reducing components are spaced apart along a length of the microcapillary tube. The anode and the cathode generate an electric field along the length of the microcapillary tube, and the plurality of electric field reducing components selectively reduce the electric field at spatial intervals along the length of the microcapillary tube.

1. A method of separating analytes in a microcapillary tube, the method comprising:
 positioning a plurality of electric field reducing components spaced apart along a length of a microcapillary tube, 
 filling the microcapillary tube with an analyte solution; 
 generating an electric field along the length of said microcapillary tube, the plurality of electric field reducing components selectively reducing the electric field at spatial intervals along the length of the microcapillary tube; and 
 switching the electric field on and off to separate a plurality of analytes in the analyte solution along a length of the microcapillary tube, wherein the plurality of analytes freely diffuse when the electric field is off such that a net force on the plurality of analytes is approximately zero. 
 
     
     
       2. The method of  claim 1 , wherein the plurality of electric field reducing components includes a plurality of high dielectric components having a dielectric constant greater than about 80. 
     
     
       3. The method of  claim 2 , further comprising forming the plurality of high dielectric components of strontium titanate. 
     
     
       4. The method of  claim 2 , further comprising forming the plurality of high dielectric components of a material having a dielectric constant of at least about 100. 
     
     
       5. The method of  claim 2 , further comprising forming the plurality of high dielectric components in a series of circumferential rings around an outer surface of the microcapillary tube. 
     
     
       6. The method of  claim 1 , wherein the plurality of electric field reducing components comprise a plurality of electrodes. 
     
     
       7. The method of  claim 6 , wherein the plurality of electrodes include electrically conducting wires forming circumferential rings around an outer surface of the microcapillary tubes. 
     
     
       8. The method of  claim 1 , wherein said switching step comprises activating the electric field for an activation duration of between about 0.1 ms and about 100 seconds and deactivating the electric field for a deactivation duration of between about 0.1 ms and about 100 seconds. 
     
     
       9. The method of  claim 1 , wherein said generating step comprises generating the electric field at a voltage of at least about 1,000 V/m. 
     
     
       10. The method of  claim 1 , wherein said generating step comprises generating the electric field at a voltage of at least about 30,000 V/m. 
     
     
       11. The method of  claim 1 , wherein the analyte solution comprises an aqueous fluid and a plurality of analytes selected from the group consisting of nucleic acids, amino acids, peptides, proteins, nucleosides and nucleotides, small organic compounds, inorganic ions, organic acids, vitamins, steroids, carbohydrates, hormones or drugs, and cells. 
     
     
       12. The method of  claim 1 , wherein said microcapillary tube has a diameter of about 50 μm, said plurality of electric field reducing components has a length along a primary axis of said microcapillary tube of about 0.1 mm, and said plurality of electric field reducing components are separated by about 0.9 mm. 
     
     
       13. The method of  claim 1 , further comprising calculating the minimum number of the plurality of electric field reducing components to separate two or more of the plurality of analytes. 
     
     
       14. The method of  claim 1 , further comprising, calculating the minimum number of periods in which the electric field is switched on and off to separate two or more of the plurality of analytes. 
     
     
       15. The method of  claim 1 , wherein switching the electric field on and off separates the plurality of analytes in the analyte solution along a straight line along the length of the microcapillary tube. 
     
     
       16. The method of  claim 1 , wherein when the electric field is on, electroosmotic flow in the microcapillary tube and the electric field together produce a net force on analytes in the microcapillary tube such that the net force in a first plurality of regions in the microcapillary tube is in a first direction and the net force in a second plurality of regions in the microcapillary tube is in a second direction that is opposite the first direction. 
     
     
       17. A method of separating analytes in a microcapillary tube, the method comprising:
 filling a microcapillary tube with an analyte solution; 
 generating a non-uniform electric field along a length of a microcapillary tube; and 
 switching the non-uniform electric field on and off to separate a plurality of analytes in the analyte solution, wherein the plurality of analytes freely diffuse when the electric field is off such that the net force on the plurality of analytes is approximately zero. 
 
     
     
       18. The method of  claim 17 , wherein said generating comprises positioning electrodes along the length of the microcapillary tube. 
     
     
       19. The method of  claim 18 , wherein the electrodes are wire rings configured to circumferentially surround the microcapillary tube. 
     
     
       20. The method of  claim 17 , wherein said generating comprises positioning high dielectric components along the length of the microcapillary tube. 
     
     
       21. The method of  claim 17 , wherein switching the electric field on and off separates the plurality of analytes in the analyte solution along a straight line along the length of the microcapillary tube. 
     
     
       22. The method of  claim 17 , when the electric field is on, electroosmotic flow in the microcapillary tube and the electric field together produce a net force on analytes in the microcapillary tube such that the net force in a first plurality of regions in the microcapillary tube is in a first direction and the net force in a second plurality of regions in the microcapillary tube is in a second direction that is opposite the first direction.